January 19 – I Got Stripes

Today’s factismal: Zebras are black with white stripes.

Zebras are fun critters. They look like punk rock horses, they run like slalom skiers in a field of moguls, and they kick like a mule. But anyone who has ever seen a zebra will agree that the most interesting thing about zebras is their stripes. Based on studies of zebra embryos, we know that their body is black with white stripes because the black skin develops first on the embryos. But that is about all that we know for sure; we still don’t know why zebras have stripes.

Two zebras discussing if they are black with white stripes or white with black stripes (My camera)

Two zebras discussing if they are black with white stripes or white with black stripes
(My camera)

We know that having stripes has to give zebras some sort of an advantage or they wouldn’t have them. But what is it? Right now, there are five competing hypotheses. Some biologists think that the stripes act as a sort of bar code, helping one zebra know which zebra is which. And some think that the stripes serve as camouflage when the zebra is standing still. The vertical stripes blend in with the outlines of tall grass and trees, making it harder to see the zebra. Another group of biologists thinks that the stripes act as “dazzle camouflage”; when a group of zebras run, the moving stripes blend together and make it harder to pick out any single zebra for lunch. Still other biologists think that the stripes may act to keep flies away by confusing them. (See, camouflage isn’t all about lions.) And a fifth group has done some work showing that the stripes may act as a sort of air conditioner for zebras.

Zebras doing their camouflage bit (My camera)

Zebras doing their camouflage bit
(My camera)

But why would a zebra need an air conditioner? Because they aren’t very good at digesting their food, that’s why. Because zebras don’t do a good job of extracting nutrients from the grass that they eat, they have to eat a lot more grass which means that they spend a lot more time out in the hot sun chomping down on tough grasses. And that’s when a built-in air conditioner would be pretty handy. There is some support for the idea; a recent study has found that zebras in hotter areas have better-defined stripes. But that would also serve to hide the zebras from flies, which are more common in hotter, wetter regions. And there is similar support for each of the other ideas.

A zebra does its Steve Austin impression (My camera)

A zebra does its John Cena impression
(My camera)

So if we know what color a zebra’s stripes are but not why they have them, who knows what else might we learn by studying these animals? And the first way to study zebras (or any other mammal) is to know where they are. And that’s where you come in! MammalMap is looking for volunteers just like you to report where and when they see which mammals in Africa. Not in Africa? NO worries – you can still contribute by helping to identify the mammals that other folks have seen. To take part, herd on over to:
http://mammalmap.adu.org.za/

January 18 – Pass The Marshmallows!

Today’s factismal: Lava-roasted hamburgers is a traditional meal for geologists working on volcanoes.

Let’s face it; geologists are weird. (Truth in advertising: I’m a geophysicist, which is just like a geologist only I do math. Back to the geologists…) They travel to exotic places in order to look at rocks and drink beer. They spend weeks in the field looking at rocks and drinking beer. And then they take their new rocks back to the lab where they look at the rocks and drink beer. And by doing this they have learned some amazing things about our planet (and others). With a little help from geophysics, they have learned how mountains form and why we have oceans (it all has to do with the density of the rocks). They have discovered what makes earthquakes and why planets are round. And most amazingly, they have learned how to cook with lava.

Geologists at work, measuring how fast lava flows (Image courtesy USGS)

Geologists at work, measuring how fast lava flows
(Image courtesy USGS)

Of course, the beer probably had something to do with the last. When you are out in the field for weeks at a time with nothing to look at but ricks and dirt-encrusted geologists, you start to look for a source of amusement. And cooking with lava is almost as amusing as it is dangerous; though there have been no deaths reported from cooking with lava, there have been a lot of near-misses. That’s because most people (geologists included) don’t have a good idea of what lava is really like. They think of it as being like really hot water because they see glorious fire fountains spewing lava hundreds of feet into the air.

A fire fountain in Hawai'i (Image courtesy USGS)

A fire fountain in Hawai’i
(Image courtesy USGS)

But what lava is like is really, really hot fudge. It is so hot that it literally glows; you know those elements in your oven that heat up and glow – yeah, just like that, only twice as hot. And lava is thick and sticky like fudge. If you were to stand on a thick slab of fudge, then you would slowly sink into it and you’d have a heck of a time getting it off of your shoes. The same is true of lava. It is sticky and so thick that you can stand on it for several minutes before you notice that you are slowly but surely sinking into a glowing hot mass of death. (This is why geologists laugh themselves silly when Gollum sinks into the lava – it just ain’t gonna happen.)

Two geologists standing near a lava flow (Image courtesy USGS)

Two geologists standing near a lava flow
(Image courtesy USGS)

But because lava is hot and oozes slowly, it makes a great way to cook hamburgers, provided that you are suicidally brave or so intellectually involved that you forget about the danger (either of which is a good description of your average geologist). The heat sears the hamburgers so that they stay juicy, and it is intense enough that they cook quickly minimizing the amount of time you have to spend next to an open oven that will roast you alive given half a chance. And so, when volcano geologists work near an active lava flow, it is traditional for them to cook hamburgers on it. To learn more about volcanoes and geologists, why not head on over to the USGS Volcano web site:
http://volcanoes.usgs.gov/

January 17 – The Rainbow Connection

It is Saturday, which means that it is time for another Secret Science Society adventure.This week Mary and Peter discover how to go to the end of the rainbow!

Peter and Mary were sitting on his porch, taking refuge from a late afternoon shower when suddenly she gasped. “Look! A rainbow! Isn’t it beautiful?”

“Do you want to find its end and steal the pot of gold?” asked Peter.

“Don’t be silly,” she replied. “There are no such things as leprechauns. But I wonder..”

“What?”

“Do rainbows really have an end?”

“I don’t know,” said Peter. “But I know who will! Mr. Medes!”

Together, the two of them jumped on their bikes and rode over to their science teacher’s house. As they rode up, they saw him spraying the ground with a sprinkler as he stared at the sidewalk.

“What are you doing?” demanded Mary.

“Looking for rainbows,” Mr. Medes replied.

“Aren’t rainbows in the sky? And do they have ends?” asked Peter.

“Rainbows are where you make them,” said Mr. Medes. “And right now, I’m trying to make them with this sprinkler.”

“How?” the pair chorused.

Holding up a triangular glass bar, he said “to understand that, you’ll need this prism. What do you think will happen if you shine a light through the prism?”

“Nothing,” Peter replied. “The light will just go straight through.”

“I think that it will bend”, said Mary.

“Ok, let’s see!”

What do you think will happen? Do the experiment!

 

 

 

The pair bent over the prism as they carefully moved it up and down from the sidewalk.

“Hey! There’s a rainbow here!” Peter exclaimed.

“That’s right,” said Mr. Medes. “The sunlight is being bent by the prism, just like Mary said it would be. But different colors of light get bent by different amounts. As a result, the prism spreads the light out into a rainbow.”

“Is that why I can see colors around the edges of things when I wear my mother’s glasses?” asked Mary.

“Yes; that’s called chromatic aberration. Astronomers and photographers spend a lot of time trying to make sure that it doesn’t affect their images,” explained Mr. Medes. “And it is also why we see rainbows. Each raindrop acts like a little prism, spreading the light out into a tiny rainbow. And when you are placed just right, all of those rainbows add up and you see a great big one in the sky.”

“Cool! But how does that answer our question about a rainbow’s end?” asked Mary.

“Let me show you,” replied Mr. Medes as he picked up the sprinkler once again. “See how the sprinkler makes little drops of water?”

“Like the raindrops that a storm makes!” Peter said.

“Right. And, if you turn with me so that the Sun is at our backs, watch what happens…” As the sprinkler sprayed the tiny drops in a fan, he slowly turned. Suddenly, a rainbow appeared in the mist.

“Hey! There’s a rainbow!” Mary yelped.

“Yeah – but this one is a circle!” Peter added.

“Right again! Rainbows are circles. But you are down low on the ground and the raindrops are high in the air, so it looks as if the rainbow is just an arc hitting the ground. If you were in an airplane and in just the right place, you could see a whole rainbow at once.”

“So the ends of a rainbow are just as mythical as leprechauns,” said Mary.

“Yes, but at least the rain is real!” laughed Peter. “But why did the prism make the rainbow to one side but the sprinkler make it in front?”

“Because a raindrop bends light like a prism but it isn’t shaped like a prism. Because of the shape of a raindrop, the light is reflected off of the back of the raindrop and comes back out on the same side as the Sun. That’s why most rainbow pictures don’t have the Sun; it is behind the person taking the photograph.”

“Now I get the picture,” Mary said.

Smiling, the three stood and watched as Mr. Medes turned the rainbow on and off with the sprinkler.

January 16 – Seed Pearls Of Change

Today’s factismal: The oysters in Chesapeake Bay once filtered all the water in the bay in four days; today it takes them a year.

Oysters are amazing animals. They filter feed by sucking in dirty water, passing it over their gills, and then noshing on the sediment and floating debris that gets trapped in their mucus. As they do so, they clarify the water and make it suitable for other critters to live in. At one time, there were so many oysters in Chesapeake Bay (located by Baltimore) that they could clean all of the water in the bay in just four days. Unfortunately, over the past century, the number of oysters in the bay have decreased due to over harvesting (people like to eat oysters as much as oysters like to eat crud), pollution, and changes in the water chemistry.

An oyster shares its tank with a horseshoe crab (My camera)

An oyster shares its tank with a horseshoe crab
(My camera)

How can a change in water chemistry affect an oyster? By making it harder to grow a shell. Oysters create shells (and pearls) out of calcium carbonate (CaCO3) that is dissolved in the water as calcium ions (Ca++) and carbonate ions (CO3–). But when carbon dioxide (CO2) dissolves in water it forms carbonic acid (H2CO3) which dissolves calcium carbonate; as a result, the shells of the oysters are thinner, more brittle, and take more energy to build. (This is also the cause behind coral bleaching.) And that leads to what is known in the oyster business as “lazy larva syndrome”. The young oysters have to spend so much energy building their shells that they have little left for eating or swimming. At the end of a year, oysters that grow up in a more acidic ocean are smaller and don’t reproduce well.

Bleached coral (My camera)

Bleached coral
(My camera)

The interesting thing is that it takes only a small change in ocean chemistry to create a big change in the number of lazy larvae. Thus far, the oceans have changed from a pH of 8.25 to 8.14; almost all of that change is due to increases in atmospheric CO2.  And the other interesting thing about this is that it isn’t just oysters that are affected; the change in ocean pH has led to more coral bleaching and slower growth of bony fish like tuna. So what is a citizen scientist to do?

Other than making sure your tires are inflated properly, perhaps the most powerful thing you can do is help the folks at Ventus as they map out all of the sources of CO2 in the world starting with the power plants. They hope that by producing an hour by hour map of how much CO2 is produced, we can identify easy places to cut back on CO2 without cutting back on our standard of living. If you’d like to help (or just see what they’ve found so far), then blow on over to:
http://ventus.project.asu.edu/

January 15 – Running On Empty

Today’s factismal: The Colorado River powers some $1,400,000,000,000 in economic activity.

There is no denying the power of a river. Rivers can sweep away towns and topsoil, carve mountains, and generate electricity. They water our fields and move our goods. And yet, rivers are running into problems. And no river is in more trouble right now than the Colorado. Born in the mountains of Wyoming and Colorado, the Colorado River drains seven different states and carries more than four and a half cubic miles of water along its 1,450 mile length. Along the way, the mighty Colorado River provides water to people living in Los Angeles and to farmers feeding the nation from their fields in the Imperial Valley. It makes dusty Las Vegas bloom and cools Flagstaff. All told, the Colorado River is responsible for some $1,400,000,000,000 in economic activity.

The Colorado River Basin includes seven states (Image courtesy Bureau of Reclamation)

The Colorado River Basin includes seven states (Image courtesy Bureau of Reclamation)

And the Colorado River is hardly the only river in the USA. All told, All told, there are more than 250,000 rivers in the USA and they stretch a total of 3,600,000 miles. They range from the the mighty Missouri (2,540 miles) to the tiny Roe River (201 ft), these riparian passages push 48,000,000 gallons of water and sediment into the ocean every second. If you were to catch the water flowing from America’s rivers with Olympic swimming pools, you’d fill up 72 of them every second. Yet, even though these rivers are essential to supporting both our life and our economy, nearly half of them are too polluted to fish from!

There are 3,600,000 miles of river in the USA (Image courtesy AAA)

There are 3,600,000 miles of river in the USA
(Image courtesy National Atlas)

Today, scientists, politicians, and ordinary citizens are working to develop plans to help save America’s rivers. If you’d like help, then consider joining a Riverwatch program (or starting your own!):
http://www.coloradowater.org/River%20Watch
http://cwriverkeepers.wikispaces.com/Home+Page
http://www.georgiaadoptastream.org/

January 14 – The Spottiest Place On Earth

Today’s factismal: One person went to Disneyland with the measles; by the end of her day, she had infected at least 26 other people.

Every day, some 41,000 people stream through the gates of Disneyland looking to have some fun. ANd, not surprisingly, a few of those folks are sick. Usually, they have a cold or the flu but sometimes they have something worse. That was the case this last December when a young woman who had just contracted measles (she didn’t know about it) went to the park. By the end of the day, she had spread the disease to at least 26 other people who have since become ill. Her case is a perfect way to explore why we vaccinate against measles and what happens when we don’t.

Why do we vaccinate?
Put as simply as possible, measles is a deadly disease. Sure, you probably heard tales from your grandparents about getting measles and getting over it. Back in the day, getting measles was easy both because so many kids had it and because it was so virulent; approximately 90% of the people exposed to measles would come down with it. But what you grandparents probably didn’t tell you is about all of their friends and neighbors who didn’t get over the disease. Measles is considered to be one of the deadliest of childhood diseases; back in the days before wide-spread vaccination, measles would kill 500 children in the US alone. Even today, measles kills hundreds of thouseands of people each year. In 2013 (the last year with complete data), measles killed an estimated 145,700 people. That number would have been much higher without vaccination; rates have increased to 84% world-wide (and nearly 100% in the US), which has reduced measles deaths by some 75% in the past decade. Put another way, thanks to the MMR vaccine, there are 437,100 people walking around who would have died from the measles in 2013; for comparison, there were some 19 deaths associated with the MMR vaccine.

A comparison of the deaths caused by measles and those caused by vaccines; the vaccine deaths were exaggerated for clarity. Each face represents 1,000 deaths.

A comparison of the deaths caused by measles and those caused by vaccines; the vaccine deaths were exaggerated for clarity. Each face represents 1,000 deaths.

How effective are vaccines?
Vaccines have come a long way since Jenner took the pus from a cow’s sores and used it to prevent smallpox. Today’s vaccines are clean, effective, and safe. How safe are they? Last year, more than a billion vaccinations were given in the US alone; there were fewer than a million adverse reactions, the vast majority of which were mild fevers and aches – no deaths from vaccines were reported last year. And vaccines are generally effective. Based on current data, the MMR vaccine is about 99% effective in preventing the disease; that is, if you give the vaccine to 41,000 people and expose each them to the virus, you would only see about 370 cases of the disease. But vaccines in the US are even more effective thanks to herd immunity.

What is herd immunity?
Put simply, herd immunity is the idea that a disease can’t spread if it can’t find someone to spread to. If you catch a cold and go to work, odds are that there will be a couple of people hating you next week because they’ll have caught the cold from you. And then their kids will curse you because they caught the disease from their folks who caught it from you. And then their teachers will curse you because they caught the disease from the kids who caught it from the parents who caught it from you. You would have started an outbreak because there simply isn’t an effective vaccine against the common cold (which is actually a whole bunch of related viruses and not a single disease).
But there is a vaccine that works against the flu. If you catch the flu and go to work and everyone there is vaccinated, you won’t be able to pass along the virus, so the outbreak will stop with you. Even if their kids haven’t had the flu vaccine, they can’t catch it because their parents can’t transmit it to them. They have herd immunity.

A simplified view of herd immunity

A simplified view of herd immunity

The Disneyland outbreak provides a great example of herd immunity. If all 41,000 people at Disneyland that day were vaccinated against the measles, then 1% of them would have had vaccinations that didn’t work. That means that there would have been 410 people who could have gotten ill; if they were all exposed to the virus, then we would have seen some 370 cases (because only 90% of the folks would have caught the measles). Instead, we’ve only seen 26 cases. That’s because the person who brought the disease to Disneyland didn’t cough in the face of everyone at the park; she only interacted with a few thousand of them. If those people hadn’t been vaccinated, then they would have been able to pass the disease to other people. But htey were vaccinated which made them immune which prevented them from carrying the disease. As a result, only the 30 or so people whose vaccinations didn’t take that she interacted with directly could get the disease.

Of course, measles isn’t the only disease that can be prevented with a vaccine. Hepatitus, influenza, smallpox (now thankfully extinct), rubella, mumps, HPV, tuberculosis, and dozens of other diseases can be prevented by vaccination saving hundreds of thousands of lives every year. And if you’d like to help doctors improve the vaccines we have and develop new ones, then why not GoViral? This project asks participants to send them a sample of saliva whenever they feel ill; the samples will be analyzed to detect emerging viruses and to help develop new techniques to tackle them:

http://www.goviralstudy.com/

January 13 – Leapin’ Rhaphidophoridae!

Today’s factismal: The noise given off by crickets is called stridulation (“shrill sound”).

There are a lot of people who don’t like crickets of any sort. They think that the crickets are dirty, filthy, disgusting critters with no redeeming social values whatsoever. Obviously, they’ve confused  crickets with politicians (or cockroaches) because crickets are among the most useful insects out there. Crickets clean our houses and fields by feasting on dead plants, fungi, and even eat their own dead. They help aerate the soil by digging burrows and fertilize it with their droppings. And while they do all this, they chirp a happy song in a process that scientists call stridulation (from the Latin for “shrill sound”).

A male field cricket. Despite their fearsome look, the spurs on his legs are not used to make sound! (Image courtesy Luis Fernández García)

A male field cricket. Despite their fearsome look, the spurs on his legs are not used to make sound!
(Image courtesy Luis Fernández García)

They do this not with their vocal chords (because they don’t have vocal chords – Jimminy was really a mute!) but by rubbing one wing against the other. The wings of a cricket are covered with fine serrations like a knife; when these flick against the wing, it acts like a big drum that makes and amplifies the sound. In many species, the rate and character of the chirping can be used to tell what the cricket has in mind. A male cricket’s “calling song” is loud and fast and intended to lure females near and drive males away. If another male gets too close, an aggressive “go away” song is heard. But if a female cricket wanders by, the male will sing a low and quiet courtship song. And if he is lucky in love, then he celebrates with a short “copulatory song” (usually sung in locker rooms).

But crickets in America are facing their worst nightmare right now. All of the best places to live and all of the good foods are being taken over by a pair of invasive camel crickets (weta) from Asia. In one survey done by citizen scientists like yourself, up to 88% of the houses had one of two species of Asian camel crickets while only 12% of the houses had a native camel cricket (which gets along better with our native crickets than the invaders do). So what can you do?

A Camel cricket, close up and personal(Image courtesy Your Wild Life)

A Camel cricket, close up and personal
(Image courtesy Your Wild Life)

Count crickets! Winter is the perfect time to look around and see what sort of cricket lives in your house. That’s because crickets and camel crickets have moved in from the cold and are easier to spot than they would be in a field or on a tree. If you spot a cricket or a camel cricket, take a picture of it and send the picture to the Camel Cricket Census. they are now in their third year of collecting data and hope to have results for the whole of the United States very soon. To reach them, chirp at:
http://crickets.yourwildlife.org/